Since the widespread introduction of antibiotics in the 1940s, the same storyline has repeated itself over and over again: new antibiotic is introduced and then resistant variants emerge and quickly spread, effectively limiting the utility and lifespan of the drug. From an evolutionary biology perspective, this is not surprising; indeed, resistant mutants are expected to arise when any lifeform with the ability to rapidly reproduce and mutate is faced with a direct selective pressure, especially when a single drug is used against a single target. Staphylococci are frequently the cause of hospital infections such as infections from implanted medical devices. Many Staphylococci strains have become resistant to many modern day antibiotics. Improved therapies are needed.
One proposed strategy to overcome the problem of resistant variants is to indirectly attack bacteria by interfering with their means of communication, also known as quorum sensing. Targeting microbial communication makes sense because bacteria coordinate many of their virulence and pathogenesis pathways through these systems. Quave et al., report quorum sensing inhibitors of Staphylococcus aureus from botanical extracts. Planta Med. 2011, 77(02):188-95.
Castanea sativa (chestnut) is a flowering plant in the family Fagaceae which can be found in Europe. See Braga et al., Nat Prod Res., 2015, 29(1):1-18. Almeida et al. report in vivo skin irritation potential of a Castanea sativa (Chestnut) leaf extract. Basic & Clinical Pharmacol Toxicol, 2008, 103(5):461-7. See also Almeida et al. J Photochem Photobiol B: Biol, 2015, 144(0):28-34. Henry et al. report cosmetic compositions containing an extract of leaves of the Castanea sativa plant and cosmetic treatments. U.S. Pat. No. 8,067,044 (2011).
Garo et al., report asiatic acid and corosolic acid enhance the susceptibility of Pseudomonas aeruginosa biofilms to tobramycin. Antimicrob Agents Chemother, 2007, 51(5):1813-7. See also Rangasamy et al. South African J Botany, 2014, 93:198-203.
Wong et al. report aqueous methanolic extracts of Melastoma malabathricum L. exhibited antibacterial activity. Nat Prod Res, 2012, 26(7):609-18
Perioni et al. report a survey on the natural ingredients used in folk cosmetics, cosmeceuticals and remedies for healing skin diseases. J Ethnopharmacol, 2004, 91(2-3):331-44.
References cited herein are not an admission of prior art.